I'm a huge fan of Etymotic for overall accuracy. Those who enjoy heavy bass may not like them, and the depth in which most of their IEMs insert can also be invasive at first. They are, hands down, the best passive isolating IEMs I've ever used.
I use the HF2s with Monster supertips (Probably the only thing I'd ever buy Monster branded) for better fit, however I also have experience with the older ER6is. I may be picking up a pair of MC5s to demo as well.
For In-Ear-Monitors, I will have to put in another vote for Etymotics. I have a pair of the ER6's and a pair of the ER4P's. Both offer excellent sound quality and great isolation.
For Open Cans, my vote has to go to Grado. I have a set of SR80's that I use at work. At home I have a pair of 325i's that are fantastic as well, but I use them with an external DAC and home built tube amp. I have yet to pair the 325i's with my GN, although I have a 1/4" to 1/8" converter in case I have the "need". As with all open cans, there is absolutely NO isolation for you or your neighbors on public transportation.